The invention relates to fluid horsepower control systems, and it more particularly pertains to horsepower control systems for atmospheric variable delivery pumps.
Fluid horsepower control systems for atmospheric variable delivery pumps are known, for example, in the Weisenbach U.S. Pat. No. 3,191,382, which limits maximum system pressure by means of a pressure compensator, and which includes additional controls for maintaining a constant, relatively small pressure differential across a distributing valve at times when the valve is open and fluid is being metered to a load. This system provides a substantially constant discharge pressure for the pump which is substantially lower than the compensator setting during periods when the distributing valve is closed. Thus, the pump flow and pressure is maintained within specific input horsepower values, the pressure compensator and distributing valve being made displacement sensitive by means of mechanical feedback indicative of the displacement of the pump. This permits substantially full utilization of horsepower input of a prime mover.
An object of the present invention is to provide a fluid horsepower control system which substantially obviates one or more of the limitations of the described prior systems.
Another object of the present invention is to provide an improved, simplified, and less expensive fluid horsepower control system.
Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings and in part pointed out as the description of the invention progresses.